ADDA (anc. Addua)  , a river of North Italy . Its true source is in some small lakes near the head of the Fragile glen, but its volume is increased by the union with several smaller streams, near the town of Bormio, at the Raetian Alps . Thence it flows first S.W., then due W., through the fertile Valtellina (q.v.), passing Tirano, where the Poschiavino falls in on the right, and Sondrio, where is the junction with the Malero, right . It falls into the Lake of Como, at its northern end, and mainly forms that lake . On issuing from its south-eastern or Lecco arm, it crosses the plain of Lombardy, and finally, after a course of about 150 m., joins the Po, 8 m. above Cremona . The lower course of the Adda was formerly the boundary between the territories of Venice and of Milan; and on its banks several important battles have been fought, notably that of Lodi, where Napoleon defeated the Austrians in 1796 . (W . A . B .